Morphological and molecular characterisation of a new species of Ceramonema Cobb and phylogenetic relationships within Ceramonematidae (Nematoda: Plectida)

Ceramonema is a diverse genus of free-living marine nematodes in the family Ceramonematidae. Based on the presence or distinctness of the zygapophyses, it has been divided into two groups. Genus Ceramonema is widely distributed, occurring from intertidal habitats to deep-sea environments across various tropical regions. Prior to the present study, only six Ceramonema species had been recorded from India. In this study, a new species, Ceramonema leduci Patra & Patro sp. n. belonging to the group with indistinct zygapophyses, is described from sandy sediments collected along the Gopalpur coast on the eastern coast of India. An updated identification key for the indistinct zygapophyses group, incorporating this new species, is provided herein. Additionally, SSU gene sequence was generated for this species, and a Bayesian Inference phylogenetic tree was constructed using available sequences from different genera of Ceramonematidae. The resulting phylogeny supports the novelty of the new species.http://www.zoobank.org/urn:lsid:zoobank.org:pub:50A7CB7B-9D1B-49A2-AC9D-6052115D2BEE